摘要 |
A needle type fuel injector has a needle control chamber at a pressure subject to a control valve in a control valve chamber which in an opening phase is lifted from its seat to expose the control valve chamber, connecting passages, and needle control chamber to a low pressure drain and in a closing phase is urged against the seat to isolate the control valve chamber, connecting passages, and needle control chamber from the drain. Resistance to the flow or displacement of fuel through the control valve seat is provided by a pressure regulating valve as the control valve rapidly closes against its seat, thereby reducing the rate of closure and thus the impact of the control valve on the seat. |